用Android OpenGL画Bitmap的方法

用Android OpenGL画Bitmap的方法 Haiyong Lei 用OpenGL API画BITMAP,BITMAP的W、H须为2的倍数,比如32、64、512。注意代码里的Vertices和Texture的坐标顺序。 import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.opengl.GLSurfaceView; import android.opengl.GLSurfaceView.Renderer; import android.opengl.GLUtils; import javax.microedition.khronos.egl.EGLConfig; import javax.microedition.khronos.opengles.GL10; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; public class MainActivity extends AppCompatActivity { Bitmap bitmap = null; class BitmapRender implements Renderer { /* the border of bitmap V3 ------ V4 | | | | | | V1 ------ V2 */ float borderVerticesCoord[] = { // x, y, z -1.0f, -1.0f, 0.0f, // V1 - left bottom 1.0f, -1.0f, 0.0f, // V2 - right bottom -1.0f, 1.0f, 0.0f, // V3 - left top 1.0f, 1.0f, 0.0f, // V4 - right top }; float bitmapTextureCoord[] = { // x, y 0.0f, 1.0f, // V3 - left top 1.0f, 1.0f, // V4 - right top 0.0f, 0.0f, // V1 - left bottom 1.0f, 0.0f, // V2 - right bottom }; FloatBuffer borderVerticesBuffer = null; FloatBuffer bitmapTextureBuffer = null; int bitmapTextureHandle = -1; private void loadBitmapTexture(GL10 gl) { int[] textures = new int[1]; gl.glGenTextures(1, textures, 0); bitmapTextureHandle = textures[0]; gl.glBindTexture(GL10.GL_TEXTURE_2D, bitmapTextureHandle); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR); //gl.glTexParameterf(GL10.GL_TEXTURE_2D, // GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); //gl.glTexParameterf(GL10.GL_TEXTURE_2D, // GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); } private void deleteBitmapTexture(GL10 gl) { int[] textures = new int[1]; textures[0] = bitmapTextureHandle; gl.glDeleteTextures(1, textures, 0); } private void buildBitmapTextureBuffer() { ByteBuffer tb = ByteBuffer.allocateDirect(bitmapTextureCoord.length * 4); tb.order(ByteOrder.nativeOrder()); bitmapTextureBuffer = tb.asFloatBuffer(); bitmapTextureBuffer.put(bitmapTextureCoord); bitmapTextureBuffer.position(0); } private void buildBorderVertexBuffer() { ByteBuffer vb = ByteBuffer.allocateDirect(borderVerticesCoord.length * 4); vb.order(ByteOrder.nativeOrder()); borderVerticesBuffer = vb.asFloatBuffer(); borderVerticesBuffer.put(borderVerticesCoord); borderVerticesBuffer.position(0); } private void drawBitmap(GL10 gl) { gl.glBindTexture(GL10.GL_TEXTURE_2D, bitmapTextureHandle); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); if (borderVerticesBuffer == null) buildBorderVertexBuffer(); if (bitmapTextureBuffer == null) buildBitmapTextureBuffer(); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, borderVerticesBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, bitmapTextureBuffer); gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, borderVerticesCoord.length / 3); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); } @Override public void onSurfaceCreated(GL10 gl, EGLConfig config) { gl.glEnable(GL10.GL_TEXTURE_2D); } @Override public void onSurfaceChanged(GL10 gl, int width, int height) { gl.glClearColor(0, 0, 0, 1); gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glViewport(0, 0, width, height); } @Override public void onDrawFrame(GL10 gl) { if (bitmapTextureHandle == -1) loadBitmapTexture(gl); drawBitmap(gl); } } GLSurfaceView glSurfaceView = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.lotus); glSurfaceView = new GLSurfaceView(this); glSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0); // need by emulator glSurfaceView.setRenderer(new BitmapRender()); setContentView(glSurfaceView); } @Override public void onPause() { glSurfaceView.onPause(); super.onPause(); } @Override public void onResume() { super.onResume(); glSurfaceView.onResume(); } }